JPH1191240A - Ink jet recording paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording paper wherein a damage (running trace, spur trace) on the surface of the paper especially by a paper feeding roll being provided at the carrying part of an ink jet printer, does not outstand, regarding the ink jet recording paper which is excellent in gloss and ink jet recording property. SOLUTION: For this ink jet recording paper, at least one layer of a recording layer is provided on a paper supporting body, and the 75 deg. glossiness (JISZ8741) on the surface on which a recording is applied is 30% or higher, and for such an ink jet recording paper, the internal combining strength (Tappi UM430) of the paper supporting body is 100×10<-3> ft-lb or higher. In addition, on the paper supporting body, at least one layer of a recording layer containing a pigment and an adhesive resin, is provided, and in addition, a gloss layer containing a resin is provided on the top of the recording layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording sheet excellent in gloss and ink jet recording suitability, and more particularly, to a method for preventing damage to the sheet surface (running marks and spur marks) caused by a paper feed roll installed in a transport section of an ink jet printer. Related to inconspicuous inkjet recording paper.

[0002]

2. Description of the Related Art Recording by an ink jet printer is as follows.
It is used in various fields because of low noise, high-speed recording, and easy multicoloring. As the ink jet recording paper, high quality paper devised to be rich in ink absorbency, coated paper having a surface coated with a porous pigment, or the like is applied. For example, Japanese Patent Application Laid-Open No. Sho 62-158084 discloses a method for producing ink jet recording paper having high ink absorption and high color development using fine-particle synthetic silica. However, all of these papers are mainly so-called matte ink jet recording papers having a low surface gloss, so that photographic full color recording could not be obtained. Therefore, in recent years, there has been a demand for inkjet recording paper having a high surface gloss and an excellent appearance.

[0003] In general, as a paper having a high surface gloss, a glossy coated paper coated with a plate-like pigment on the surface and further subjected to a calender treatment as required, or a wet coated layer having a mirror surface There is known a so-called cast-coated paper obtained by pressing and drying the surface of a heating drum and copying the mirror surface. This cast coated paper has higher surface gloss and better surface smoothness compared to normal coated paper with super calender,
Because of its excellent printing effect, it is used exclusively for applications such as high-quality printed matter, but when used for ink jet recording paper, it has various difficulties. That is, generally, the conventional cast coated paper is, for example, US Pat.
No. 6 discloses. A film-forming substance such as an adhesive in the pigment composition constituting the coating layer transfers the mirror surface drum surface of the cast coater to obtain high gloss.
On the other hand, there is a problem that the porosity of the coating layer is lost due to the presence of the film-forming substance, and the absorption of ink during ink jet recording is extremely reduced. In order to improve the ink absorbency, it is important to make the cast coating layer porous so that the ink can be easily absorbed, and for that purpose, it is necessary to reduce the film formability.
By reducing the amount of the film-forming substance, the gloss of white paper is reduced as a result. As described above, it was extremely difficult to simultaneously satisfy both the surface gloss of the cast coated paper and the suitability for inkjet recording.

As a method for solving the above problem, a glass transition point of 40 ° C. or higher obtained by polymerizing a monomer having an ethylenically unsaturated bond on a base paper provided with an undercoat layer mainly composed of a pigment and an adhesive. A coating liquid containing the copolymer composition as a main component is applied to form a coating layer for casting, and the coating layer for casting is pressed against a heated mirror-surface drum while the coating layer is wet, and dried. By finishing
The present inventors have found that a cast paper for ink jet recording having excellent gloss and ink absorbency can be obtained, and proposed the method in Japanese Patent Application Laid-Open No. 7-89220. According to the above technique, a recording sheet excellent in surface gloss and ink jet recording suitability can be obtained. However, a recording sheet excellent in surface gloss, specifically, a surface gloss of 75 ° (JISZ
8741) is 30% or more of the recording sheet, there is a problem that damage to the paper surface (hereinafter referred to as a spur mark) due to spurs such as gears of a paper feed roll installed in the conveyance unit of the inkjet printer is visually noticeable. is there. Especially,
In recent years, high-definition printers have made it possible to obtain photographic images, but in this case, the number of spurs such as gears attached to the transport roll after printing has been increasing in order to increase the transport accuracy of the printer. At present, spur marks are becoming more noticeable.

[0005]

The printed recording medium is conveyed from the printing surface side while being pressed by, for example, a metal gear (spur). The print portion swells with the ink, and a spur hits the softened portion of the recording body, leaving a mark. The present invention solves such a problem, and provides an inkjet recording paper excellent in inkjet recording suitability such as gloss, print density, ink absorbency, and recording image quality.

[0006]

According to the present invention, at least one recording layer is provided on a paper support, and the surface has a glossiness of 75 ° (J).
ISZ8741) of 30% or more, the internal bond strength of the paper support (Tappi).
UM 403, also referred to as Z axis strength) is 100 × 10
^-3 ft-lb or more.

[0007] The present invention includes the following aspects. [1] At least one recording layer is provided on a paper support (also referred to as base paper), and a 75 ° glossiness (JISZ8
741) is 30% or more, the internal bond strength of the paper support (Tappi UM4
03: an inter-fiber bonding test by an internal bonding tester, also referred to as Z-axis strength) of 100 × 10 ⁻³ ft-lb or more. [2] At least one recording layer containing a pigment and an adhesive resin (also simply referred to as an adhesive) is provided on a paper support, and a gloss layer containing a resin is further provided thereon. ] The ink jet recording paper as described above. [3] The glossy layer is coated with a coating solution containing a resin, and while the obtained coating layer is in a wet state, or once dried and re-wetted, is pressed against a heated mirror drum and dried. The ink jet recording paper according to [1] or [2], wherein the ink jet recording paper is finished.

[4] The pulp used for the paper support has a freeness (CSF: JISP-8121) of 300-4.
The ink jet recording paper according to any one of [1] to [3], which is 50 ml. [5] The inkjet according to any one of [1] to [4], wherein the paper support contains at least calcined kaolin or amorphous silica, and the content is 1 to 15% by weight. Recording sheet. [6] The paper support contains calcined kaolin or amorphous silica, the calcined kaolin has an average particle diameter of 0.5 to 5 μm, a specific surface area of 5 to 50 m ² / g, and the amorphous silica has an average particle diameter of 5 to 50 m ² / g. The inkjet recording paper according to any one of [1] to [5], which has a diameter of 1 to 50 μm and a specific surface area of 50 to 300 m ² / g. [7] The gloss layer contains a resin and amorphous silica fine particles, and the amorphous silica fine particles have an average primary particle diameter of 3 nm or more and 40 nm or less and an average secondary particle diameter of 10 nm or less.
The inkjet recording paper according to any one of [2] to [6], wherein the inorganic silica fine particles have a diameter of 300 nm or more and 300 nm or less.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The base paper used in the present invention is mainly composed of pulp such as wood, and the base paper has a Z-axis strength, that is, an internal bond strength of 100 × 10 ⁻³ ft-lb or more. And The Z-axis strength is more preferably 150 × 10 ⁻³ ft-lb or more. The Z-axis strength is obtained by measuring the average energy required to separate the paper into two layers, and a specific measuring method is shown in TappiUM403. The upper limit is not particularly defined, but if it exceeds 300 × 10 ⁻³ ft-lb, the effect is saturated, and print bleeding, cockling, curling, and the like may be deteriorated. The present inventors,
As a result of repeated studies to reduce the spur marks, it was found that there is a correlation between the Z-axis intensity of the base paper and the level of the spur marks. That is, the 75 ° glossiness (JISZ8741) of the surface is 30%.
It has been clarified that the higher the Z-axis strength of the base paper of the inkjet recording paper described above, the lower the occurrence of spur marks. It is considered that the reason is that the base paper swells and becomes flexible due to the ink during ink-jet recording, and that a spur mark is likely to be formed on the printed portion. It is presumed that the bond is strong and that the ink does not easily swell even if it penetrates.

As pulp used as a main component of base paper, chemical pulp such as LBKP and NBKP, GP, TM
Mechanical pulp such as P; and waste paper pulp such as DIP. Generally, the lower the freeness (CSF) of the pulp, the higher the Z-axis strength of the base paper tends to be. However, if the freeness (CSF) is too low (for example, less than 300 ml), cockling after printing (unevenness due to swelling of a printed portion) is deteriorated, and furthermore, drainage is reduced, which impairs operability in the paper making process. In addition, it may be difficult to control the curl of the manufactured base paper. In addition, since the air permeability of the base paper is reduced, when the coating is performed by the cast method, it is difficult for moisture to escape, and the paper is blurred and the operability is significantly reduced.

JISP-812 pulp used for base paper
The freeness (CSF) specified in 1 is 300 to 45
0 ml is preferred. More preferably, the freeness is 350 to 440 ml. The reason is presumed that if the freeness of the pulp is 450 ml or less, the pulp becomes more flexible and fibrillated, so that the fiber-to-fiber bonds of the base paper become stronger, and it becomes difficult for the ink to permeate to swell. . However, if the freeness is less than 300 ml, cockling after printing (unevenness due to partial swelling of the printed portion) is deteriorated, and the drainage is further reduced, which may hinder the operability in the paper making process. Controlling curled base paper may be difficult. In addition, since the air permeability of the base paper is reduced, when the coating is performed by the cast method, it is difficult for moisture to escape, and the paper may be blurred or the operability may be significantly reduced.

The freeness can be adjusted by beating. Beating has the function of softening and fibrillating pulp fibers by mechanical means (unraveling the pulp surface or inside to make fine fibers), and increasing the bond between pulp fibers of the paper. Generally, a beater such as a beater, a Jordan, a conical refiner, a drum refiner, and a disc refiner is used. Freeness is adjusted by the energy required for processing in the beating apparatus. Generally, the more the energy of beating is applied, the lower the freeness (CSF) becomes.

As base paper materials, in addition to pulp, pigments (fillers), adhesives, sizing agents, fixing agents, retention agents, cationizing agents, paper strength agents, dyes, fluorescent whitening agents, etc. are appropriately used. Is done. As the pigment, amorphous silica, calcined kaolin, calcium carbonate, titanium oxide and the like are blended for the purpose of imparting opacity, preventing penetration of the ink, and imparting ink absorbency. For the purpose of imparting ink absorbability, amorphous silica and calcined kaolin are preferred. Particularly, as amorphous silica, the average particle size is 1 to 50 μm, and the specific surface area is 50 to 30.
0 m ² / g, calcined kaolin with an average particle size of 0.5
Those having a specific surface area of 5 to 50 m ² / g are preferred.

However, in the ink jet recording paper of the present invention, if the amount of the pigment is too large, the interlayer strength tends to decrease. On the other hand, if the amount of the pigment is small, the interlayer strength tends to be improved, the swelling of the base paper by the ink is suppressed, and spur marks are not easily formed, but the ink absorbency is reduced, and bleeding and unevenness of printing occur. In some cases, strike-through (show-through) of the ink may be conspicuous. Although the amount of the pigment depends on the type, when the pigment is silica or calcined kaolin, the amount of the pigment is preferably 1 to 15% by weight based on the base paper (paper support) for the above-described reason, More preferably, it is 2 to 8% by weight. The pigment content relative to the base paper can be determined by measuring the ash content of the base paper. On the base paper, starch,
Coating polyvinyl alcohol or cationic resin, etc.
It can be impregnated to improve the surface strength or adjust the penetration of the coating layer. Further, it is preferable that the surface of the base paper is smoothed with a calender or the like, since the formation of the coating layer becomes uniform.

It is to be noted that the penetration of the ink and the swelling of the base paper can be suppressed by adding a sizing agent or the like to the base paper or by providing a barrier layer on the base paper surface. The absorption capacity is apt to decrease, the ink is liable to bleed, and shading is apt to occur, and the image quality is likely to be inferior. The sizing degree is preferably about 1 to 100 seconds, more preferably about 2 to 50 seconds, based on 100 g / m ² paper. As described above, generally, the lower the freeness (CSF) of the pulp and the smaller the blending amount of the internal pigment, the higher the Z-axis strength of the base paper tends to be. The Z-axis strength is increased by the addition of the paper strength enhancer.
Examples of the paper strength enhancer include starch, cationized starch, vegetable gum, polyacrylamide resin, polyamide epichlorohydrin resin, and the like. Furthermore, if a polymer such as starch or polyvinyl alcohol is subjected to size press treatment on the surface of the base paper, the interlayer strength tends to increase due to impregnation of the material.

The recording layer provided on the base paper will be described. The recording layer contains a pigment and an adhesive. In the recording layer itself,
A glossing treatment may be performed by a cast finish, a super calendering treatment, or the like, but a glossy layer mainly composed of a resin and, if necessary, a pigment may be provided on the recording layer.
Examples of the pigment to be contained in the recording layer include amorphous silica (including colloidal silica), zeolite, kaolin, clay, calcined clay, zinc oxide, aluminum oxide, aluminum hydroxide, calcium carbonate, satin white, aluminum silicate, sepiolite, Various pigments known and used in the general coated paper manufacturing field, such as smectite, synthetic smectite, hydrotalcite, magnesium silicate, magnesium carbonate, magnesium oxide, diatomaceous earth, styrene plastic pigment, urea resin plastic pigment, benzoguanamine plastic pigment, etc. It can be exemplified, and can be used alone or in combination.

Among these, amorphous silica, zeolite, and aluminum oxide are preferable from the viewpoint of ink absorption, and it is particularly preferable to include amorphous silica as a main component of the pigment. As the amorphous silica, synthetic amorphous silica is preferable. Synthetic amorphous silica is roughly classified into a wet method and a dry method according to its production method. The wet method is obtained by using sodium silicate as a raw material and neutralizing with an acid to precipitate silica. The wet method is further divided into a precipitation method and a gelation method. The dry method is obtained by using silicon tetrachloride as a raw material, burning it with hydrogen and oxygen, and depositing silica. Usually, it is called white carbon, and is known as silicic anhydride, hydrated silicic acid, and the like. The average secondary particle diameter of the synthetic amorphous silica is preferably about 0.5 to 20 μm.
For the purpose of absorbing ink, the oil absorption and BE
It is desirable that the T-type specific surface area is high, but if it is too high, the viscosity of the coating composition may be too high, and the oil absorption is generally about 100 to 400 ml / 100 g, and the BET specific surface area is about 100 to 500 m ^2. Is preferred.

Examples of the adhesive include proteins such as casein, soybean protein, and synthetic protein; various starches such as starch and oxidized starch;
Polyvinyl alcohol, cellulose derivatives such as carboxymethylcellulose and methylcellulose, styrene-butadiene copolymer, conjugated diene-based polymer latex of methyl methacrylate-butadiene copolymer, acrylic polymer latex, vinyl such as ethylene-vinyl acetate copolymer Conventionally known adhesives generally used for coated paper, such as a polymer latex, may be used alone or in combination. The amount of the adhesive is not particularly limited, but is adjusted in the range of 1 to 100 parts by weight, more preferably 2 to 50 parts by weight, per 100 parts by weight of the pigment. If the amount of the adhesive is small, the strength of the recording layer may be weakened, the surface may be easily damaged, and powder may fall off. Conversely, if the amount of the adhesive is large, the ink absorbency may decrease, and the desired inkjet recording suitability may not be obtained.

The recording layer may contain a cationic compound for the purpose of fixing the dye component in the ink, increasing the printing density and imparting printing water resistance. Examples of the cationic compound include a cationic resin and a low molecular weight cationic compound (for example, a cationic surfactant or the like). A cationic resin is preferred from the viewpoint of improving the print density, and can be used as a water-soluble resin or an emulsion. Further, it can be used as a cationic organic pigment in which the cationic resin is insolubilized by means of crosslinking or the like to form a particulate form. Such a cationic pigment, when polymerizing a cationic resin, copolymerizes a polyfunctional monomer to form a crosslinked resin, or has a reactive functional group (hydroxyl group, carboxyl group, amino group, acetoacetyl group, etc.). A cross-linking agent is added to the cationic resin as needed, and the cross-linked resin is formed by heat, radiation, or the like. Cationic compounds, especially cationic resins, may also serve as adhesives.

The following are examples of the cationic resin. Specifically, 1) polyalkylene polyamines such as polyethylene polyamine and polypropylene polyamine or derivatives thereof, 2) acrylic resin having a secondary amine group, tertiary amine group, or quaternary ammonium group, 3)
Polyvinylamine, polyvinylamidines, 4) dicyan cation resin represented by dicyandiamide-formalin polycondensate, 5) polyamine cation resin represented by dicyandiamide-diethylenetriamine polycondensate, 6) epichlorohydrin-dimethylamine addition polymer , 7) dimethyldiallylammonium chloride-S
0 ₂ copolymer, 8) diallylamine salt -S0 ₂ copolymer, 9) dimethyldiallylammonium chloride polymer, 10) polymers of allylamine salts, 11) dialkylaminoethyl (meth) acrylate quaternary salt polymer, 1
2) Cationic compounds such as acrylamide-diallylamine salt copolymer. The cationic compound can be used in an amount of 1 to 100 parts by weight, more preferably 5 to 50 parts by weight, based on 100 parts by weight of the pigment. If the compounding amount is small, it is difficult to obtain the effect of improving the printing density, and if it is too large, the printing density may be reduced or the image may be blurred.

In addition, various auxiliaries such as a dispersant, a thickener, an antifoaming agent, a coloring agent, an antistatic agent and an antiseptic used in the production of general coated paper are appropriately added. The recording layer composition composed of the above materials generally has a solid content of 5 to 5.
Adjusted to about 65% by weight, the basis weight is about 20-400g / m
^A blade coater, an air knife coater, a roll coater, a brush coater, a champlex coater, a bar coater so that the dry weight is about 1 to 50 g / m ² , more preferably about ² to ²⁰ g / m ^{2 on} about ² substrates. Is applied and dried by various known and publicly used coating devices such as a gravure coater. Further, if necessary, the recording layer may be subjected to a smoothing process such as super calendering or brushing after drying.

Next, a gloss layer can be further provided on the recording layer containing the pigment and the adhesive as main components. This gloss layer is constituted by containing a resin and, if necessary, a pigment. The glossy layer is preferably made porous or liquid-permeable so as to allow the ink to pass through quickly without impairing the gloss. In order to achieve this, it is preferable to mix a pigment or select a drying condition that does not completely form a resin film within a range that does not reduce gloss. When blending a pigment in the gloss layer, the kind of pigment includes the same as those used in the undercoat layer, but in terms of gloss, transparency, ink absorption, colloidal silica, amorphous silica, Aluminum oxide, zeolite, synthetic smectite and the like are preferred, and the average particle size of the pigment is preferably 0.01 to 5 μm, more preferably 0.05 to 1 μm. If the particle diameter is less than 0.01 μm, the effect of improving the ink absorbency is poor, and if it exceeds 5 μm, the gloss and the print density may be reduced.

The average primary particle diameter of the pigment is 3 nm.
Not less than 40 nm and the average particle diameter of the secondary particles is 10 nm
When the silica fine particles having a thickness of not less than 300 nm are used, gloss and ink absorbability are particularly excellent. It is particularly preferable that the glossy layer is formed with a pigment as a main component (preferably 40 to 90% by weight, more preferably 50 to 90% by weight). In this case, since the glossy layer is excellent in ink absorption and transparency, if a cationic compound is blended in the glossy layer, the ink dye is efficiently fixed to the glossy layer, and the print density is extremely excellent in combination with the transparency of the glossy layer. Easily.

Examples of the resin for the gloss layer include organic polymers, particularly polyvinyl alcohols, aqueous urethane resins, and polymer resins obtained by polymerizing monomers having an ethylenically unsaturated bond. The aqueous urethane resin is obtained by reacting an isocyanate such as diisocyanate, triisocyanate and tetraisocyanate with a polyol. Among them, a polymer composition obtained by polymerizing a monomer having an ethylenically unsaturated bond (hereinafter, referred to as an ethylenic monomer) is suitably used. Examples of such a polymer include methyl acrylate, ethyl acrylate, butyl acrylate, and the like. Acrylic acid ester having 1 to 18 alkyl groups such as 2-ethylhexyl acrylate, lauryl acrylate, 2-hydroxyethyl acrylate, glycidyl acrylate, methyl methacrylate, ethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl Alkyl groups such as methacrylates having 1 to 18 carbon atoms, methacrylic acid esters, styrene, α-methylstyrene, vinyltoluene, acrylonitrile, vinyl chloride,
Examples include polymers obtained by polymerizing ethylenic monomers such as vinylidene chloride, vinyl acetate, vinyl propionate, acrylamide, N-methylolacrylamide, ethylene, butadiene, acrylic acid, and methacrylic acid.

The polymer may be a copolymer using two or more kinds of ethylenic monomers as necessary, or may be a polymer or a substituted derivative of the copolymer. Further, the above-mentioned ethylenic monomer is polymerized in the presence of colloidal silica, and Si—O—R (R:
(Polymer component) A functional group which reacts with colloidal silica such as a SiOH group is introduced into the polymer or copolymer in the form of a composite by bonding, or is reacted with colloidal silica to form a composite. It is also possible to use it in a different form. When this composite is used, it tends to be excellent in gloss and ink absorbency, and when it uses a casting method described later, it tends to be excellent in release from a cast drum. The composite particles are not particularly limited, but have, for example, an average particle size of about 30 to 150 nm.

The above (co) polymer composition preferably has a glass transition point of 40 ° C. or higher,
Is more preferable. When the glass transition point is low, film formation proceeds excessively during drying, and the porosity of the surface is reduced. As a result, the ink absorption rate may be reduced. In addition, the drying temperature is important. If the drying temperature is too high, the film formation proceeds too much, and the porosity of the surface is reduced. As a result, the ink absorption rate is reduced, and if the drying temperature is too low, the gloss is poor. And the productivity also decreases. As a method for providing a gloss layer, a coating liquid composed mainly of a resin and, if necessary, a pigment may be applied on the recording layer, and may be subjected to a smoothing treatment using a super calender or the like. However, preferably, a coating liquid composed mainly of a resin and, if necessary, a pigment is applied, and the coating layer is pressed against a heated mirror drum while the coating layer is in a wet state, followed by finishing by drying. Method (wet cast method) or a method of once drying and rewetting the coated layer, pressing it on a heated mirror drum, drying and finishing (rewet cast method)
However, it is preferable because an ink jet recording sheet having excellent gloss and ink absorbency can be obtained. The temperature of the heated mirror drum is, for example, 50 to 150 ° C., preferably 70 to 150 ° C.
~ 120 ° C.

Further, a coating liquid containing a resin and, if necessary, a pigment is directly applied to the heated mirror-surface drum, and the recording layer is formed while the coating layer is wet to some extent. It is also possible to employ a method of pre-pressing and drying the base material provided in advance and finishing it (precast method). Further, a coating liquid containing a resin and, if necessary, a pigment is applied on a smooth film or sheet, and the coating layer or the recording layer surface to be bonded is in a somewhat wet state. In the meantime, a method (film transfer method) in which a smooth film or sheet is peeled off and finished after being pressed against and dried on the base material can also be adopted. Pigment, defoamer, colorant, antistatic used in general printing coated paper and inkjet paper to adjust whiteness, viscosity, fluidity, etc. in the coating composition for glossy layer Various auxiliaries such as agents, preservatives, dispersants, and thickeners are added as appropriate. It is also possible to mix a cationic resin to impart ink dye fixability to the glossy layer.

When the above-mentioned gloss layer coating liquid is coated on the recording layer, a blade coater, an air knife coater,
Various known coating apparatuses such as a roll coater, a brush coater, a chaplex coater, a bar coater, and a gravure coater can be used. After that, preferably, as described above, while the coating layer is in a wet state, or after the coating layer is once dried and re-wetted, it is pressed against a heated mirror-surface drum, dried and cast-finished. In this case, the coating amount of the gloss layer coating liquid is 0.2 to 30 g / m ² , preferably 1 to 10 g / m ² in terms of dry solid content. Here, 0.2 g / m
^If it is less than ² , gloss may not be sufficiently obtained, and may be 30 g / m
^If it exceeds ² , the ink drying property may be poor or the recording density may be reduced. After the gloss layer is provided, a smoothing process can be further performed by using a super calendar or the like.

According to the present invention, a recording medium having excellent glossiness can be obtained, but the glossiness of the recording surface is 75 ° (JIS Z).
8741) is 30% or more, whereby high-quality recording with excellent image quality and photographic tone can be obtained. The gloss is preferably at least 40%, more preferably at least 65%. Although there is no particular upper limit, it is, for example, 95%.

[0030]

The present invention will be described in more detail with reference to the following Examples, but it should be understood that the present invention is by no means restricted thereto.
Parts and% in Examples are parts by weight and% by weight, respectively, unless otherwise specified. Examples 1 to 9, Comparative Examples 1 and 2, 100 parts of hardwood kraft pulp, 0 to 30 parts of calcined kaolin (average particle size: 1 μm, specific surface area: 18 m ² / g, Ansilex; Engelhard Mineral Co.), commercial sizing agent: 0. A base paper having a basis weight of 100 g / m ² was prepared by a base paper formulation comprising 2 parts, 0.75 part of starch (tapioca), 0.5 part of wet paper strength agent, and 1.5 parts of a sulfuric acid band. Pulp fleece used in each of the examples and comparative examples (CSF:
JISP-8121) is shown in Table 1. Further, calcined kaolin was blended so as to have the value shown in Table 1 as ash. Next, amorphous silica (specific surface area 340 m ² /
g, average secondary particle size 4.5 μm, 100 parts of Fine Seal X-45, manufactured by Tokuyama Corporation, 25 parts of silyl-modified polyvinyl alcohol (R1130: manufactured by Kuraray Co., Ltd.) as an adhesive, cation 5 parts of a dicyandiamide resin (NEOFIX E-117; manufactured by Nika Chemical Co., Ltd.) as a cationic resin, and a cationic acrylamide resin (Sumilet Resin SR1001; Sumitomo Chemical Co., Ltd.)
15 parts) and 0.5 parts of sodium polyphosphate as a dispersant were added to prepare a recording layer coating liquid having a solid content of 18%. This recording layer coating liquid was applied to one side of the base paper by an air knife coater so as to have a dry weight of 6 g / m ² and dried.

On the other hand, styrene-2 having a glass transition point of 75 ° C.
100 parts of a composite of methylhexyl acrylate copolymer and colloidal silica (copolymer and colloidal silica in a weight ratio of 50:50, composite particle diameter of 80 nm), and an alkyl vinyl ether / maleic acid derivative as a thickening / dispersing agent A gloss layer coating liquid comprising 5 parts of coalesced and 2 parts of lecithin as a release agent and having a solid content concentration of 25% was prepared. After applying the gloss layer coating solution on the recording layer using a roll coater, immediately press-contact the mirror surface drum having a surface temperature of 80 ° C., dry and release, and use a gloss type inkjet recording paper. I got The coating amount of the gloss layer at this time was 6 g / m ² in terms of solid content weight.

Example 10 100 parts of hardwood kraft pulp (Freeness CSF; 4
20 ml), amorphous synthetic silica (average secondary particle size 10μ)
m, specific surface area 190 m ² / g, Tokusil GUN; 4 parts by Tokuyama), commercial sizing agent 0.2 parts, starch (tapioca) 0.75 parts, wet paper strength enhancer 0.5 parts, sulfate band 1.5 Base paper formula consisting of 100 g / m ²
Base paper was made. At this time, the ash content was 3%. A recording layer and a gloss layer were provided in the same manner as in Examples 1 to 9 except that this base paper was used.

Example 11 On the base paper used in Example 5, the following coating solution for an undercoat layer was applied:
12 g / m dry weight ^TwoLike an air knife
Coating and drying. Next, the following gloss layer coating liquid
Is coated on the undercoat layer with an air knife coater.
And dry it with cold air for 20 seconds to make it semi-dry.
(Moisture percentage of 150% of dry weight), surface temperature of 100 ° C
Press against a mirror-surface drum, dry it, release it,
Inkjet recording paper was obtained. Cast coating at this time
The coating amount of the working layer is 5 g / m^TwoMet. [Coating liquid for undercoat layer (solid content 17%)] Synthetic amorphous
Silica (Fine Seal X-60; manufactured by Tokuyama, specific surface
Product 290m ^Two/ G, average secondary particle diameter 6.0 μm, primary particles
80 parts, zeolite (Toyobuilder;
20 parts, silyl-modified, average particle size 1.5 μm)
Polyvinyl alcohol (R1130; made by Kuraray) 20
Part, styrene-2-methylhexyl having a glass transition point of 75 ° C
Acrylate copolymer and colloidal particles with a particle diameter of 30 nm
Complex emulsion with Rica (copolymer and colloidal
Lica is 40:60 by weight and the particle size of the emulsion is 8
0 nm) 40 parts.

[Coating solution for glossy layer (solids concentration: 12%)]
100 parts of the following silica fine particles A, 10 parts of diallyldimethylammonium chloride-acrylamide copolymer (manufactured by Nitto Boseki Co., Ltd., trade name: PAS-J-81), cationic acrylic resin (XC-2010; Seiko Chemical, quaternary amine) Modified acrylic aqueous resin, Tg 85 ° C) 20 parts, silyl-modified polyvinyl alcohol (R1130; manufactured by Kuraray)
10 parts, 2 parts of release agent (lecithin). [Preparation of Silica Fine Particles A] Using an aqueous dispersion of synthetic amorphous silica (trade name: Fine Seal X-45, secondary particle diameter 4.5 μm, primary particle diameter 15 nm, manufactured by Tokuyama Corporation)
The pulverization operation was repeated using a pressure-type homogenizer (trade name: ultrahigh-pressure type homogenizer GM-1 manufactured by SMT) (pressurization: 500 kg / cm ² ). After the treatment, the dispersion had an average secondary particle size of 50 nm and a solid content of 12%.

Comparative Example 3 Amorphous silica (average particle size: 4.5 μm, trade name: Fine Seal X-45, manufactured by Tokuyama Corporation) was used as a pigment.
00 parts, 25 parts of silyl-modified polyvinyl alcohol (R1130: manufactured by Kuraray Co., Ltd.) as an adhesive, and dicyandiamide resin (Neofix E) as a cationic resin
-117; Nika Chemical Co., Ltd.) 5 parts, and a cationic acrylamide resin (Sumiretz Resin SR100)
1; Sumitomo Chemical Co., Ltd.) (15 parts) and sodium polyphosphate (0.5 part) as a dispersant were added to prepare a recording layer coating liquid having a solid content of 18%. This coating solution for recording layer was prepared in Example 5
8 g / dry weight on one side of the same base paper as used in
It was coated with an air knife coater and dried to obtain an ink jet recording paper so as to obtain m ² . No gloss layer is provided.

Comparative Example 4 A base paper similar to that used in Example 5 was used as it was.
Comparative Example 5 A commercially available glossy inkjet recording film (H
G101: manufactured by Canon Inc.).

Table 1 summarizes the inkjet recording aptitude, blank gloss, and print storability of the inkjet recording paper thus obtained. In addition, about the said evaluation, evaluation was performed by the following methods. [Z-axis strength, internal bond strength] Sisalkraft-SCOTT INTERNAL BOND TESTER MODEL-
B was used for measurement (TAPPI UM403). [Inkjet recording suitability] Printing was performed using an inkjet printer PM700C (manufactured by Seiko Epson Corporation). (Uniformity of solid printing portion) The printing unevenness (shading unevenness) of the solid printing portion in which two colors of cyan ink and magenta ink were mixed was visually evaluated. ：: Good level with almost no printing unevenness. Δ: Printing unevenness is somewhat noticeable, and is a level that poses a practical problem. X: Print unevenness is conspicuous.

(Ink Bleeding) Solid printing of each of the cyan ink and the magenta ink was printed with the borders in contact with each other, and the border bleeding was evaluated. : Bleeding is hardly observed. −-: Slight bleeding is seen, but there is no practical problem. ×: Bleeding is noticeable, which is a practically problematic level. (Dryability of ink) 2 of cyan ink and magenta ink
The dryness of the ink was evaluated for the solid printing portion of the color mixture. ：: No stain at all even if touched with a finger immediately after printing. ×: Stained when touched with a finger immediately after printing. (Water resistance to printing) Characters were printed with inks of black, cyan, magenta, and yellow, and three drops of water were dropped on a printed portion with a spoid. One minute later, the degree of bleeding of the print was visually evaluated. ：: There is almost no change in printing. X: Printing is disturbed.

(Print density after ink jet recording) The print density of the black solid print portion was measured by Macbeth RD-914. (Spur marks) Solid printing of a mixture of two colors of cyan ink and magenta ink was performed on the entire surface of an A4 size recording sheet, and the spur marks were visually evaluated. ◎: Spur trace is hardly seen. ：: Spur trace is slightly observed. ○-: A spur mark is slightly conspicuous, but there is no practical problem. Δ: Spur trace is somewhat conspicuous, which is a practically problematic level. ×: Spur traces are severe.

[Cockling] Solid printing of a mixture of two colors of cyan ink and magenta ink was performed on the entire surface of an A4 size recording sheet, and cockling (wrinkles after printing) was visually evaluated. : Cockling is inconspicuous. −-: Cockling is somewhat conspicuous, but practically acceptable. [Blank gloss] 75% of blank paper according to JIS-P8142
° Gloss was measured.

[0041]

[Table 1]

[0042]

As is clear from the results shown in Table 1, the ink jet recording paper of the present invention was excellent in gloss and ink jet recording suitability, and had no noticeable spur marks.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI D21H 27/00 D21H 5/00 Z (72) Inventor Masami Kubota 1-10-6 Shinonome, Koto-ku, Tokyo Oji Paper Shinonome Research Center Co., Ltd. Inside

Claims (7)

[Claims] 1. A paper support having at least one recording layer provided thereon,
In an ink jet recording paper having a 75 ° glossiness (JIS Z8741) of 30% or more on the recording side surface, the internal bond strength (Tappi UM403) of the paper support is
An ink jet recording paper having a size of 100 × 10 ⁻³ ft-lb or more. 2. An ink jet recording apparatus according to claim 1, wherein at least one recording layer containing a pigment and an adhesive resin is provided on a paper support, and a gloss layer containing a resin is further provided thereon. Paper. 3. A glossy layer is coated with a coating solution containing a resin, and while the obtained coating layer is in a wet state, or once dried and re-wetted, is pressed against a heated mirror-surface drum. 3. The ink jet recording paper according to claim 1, wherein the ink jet recording paper is finished by drying. 4. The ink jet recording paper according to claim 1, wherein the pulp used for the paper support has a freeness (CSF) of 300 to 450 ml. 5. The ink-jet recording according to claim 1, wherein the paper support contains at least calcined kaolin or amorphous silica, and the content is 1 to 15% by weight. Paper. 6. A paper support containing calcined kaolin or amorphous silica, wherein the calcined kaolin has an average particle size of 0.5 to 5 μm.
a specific surface area of 5 to 50 m ² / g in m, the amorphous silica average particle diameter 1~50μm specific surface area 50 to 300 m ²
/ G, the inkjet recording paper according to any one of claims 1 to 5. 7. The glossy layer contains a resin and fine particles of amorphous silica, wherein the fine particles of amorphous silica have an average primary particle diameter of 3 nm or more and 40 nm or less and an average secondary particle diameter of 10 nm or more. The inkjet recording paper according to any one of claims 2 to 6, comprising amorphous silica fine particles having a diameter of 300 nm or less.